Whenever I turn on my truck, the temp gage needle immediately jumps to the center of the gage. It doesn't matter if the engine is hot or cold. I did unplug the connector from the sending unit but the needle still jumped to the center when I turned the key. Maybe this wasn't the correct way to see if the sending unit was bad? Did anyone else ever have this problem? I had written about this a couple of years ago but never got an answer. I would really like to get this fixed before I really screw things up if I have an overheating problem some day.